How do people get away with it?

So recently i unintentionally got help with an assignment and was suspected of ';cheating'; the donkey teacher prolly took it to the dean and head. But my best friend, who i love dearly, she gets away with everything. She cheated a full course, got tests from a friend who previously took the class and aced the exams while the smartest people were getting like Bs, she was getting As. Then whats worse, at a school assembly she gets recognized in that VERY class! I cant handle it. But she is my best friend, and has been there for me alotttt. Everyone loves her now, and now some look at me like im the bad guy because of 1 assignment, not even an exam, a homework! I dont get life, im frusturated and dont know how to feel or what to do. I feel discouraged and its my last semester of senior year and i feel unmotivated. What do i do?How do people get away with it?
You have to live for yourself, life is never fair, I am sure there are things your friend would say wasnt fair about her life. You go through it then move on and try to be better, you have to look at yourself in the mirror and like you every night. No one else does.